Post

Unpopular opinion but if you're interested in the effects of a medical product, it's 'RCT or bust' for me. I can see the case for observational analyses when randomization isn't possible, ethical, or the condition is too rare or some other such thing, but there's no such excuse here.

Wait--so some folks should volunteer not to get vaccinated against shingles?

Placebo doesn't mean withholding the treatment, but they wouldn't get it as part of the trial. In this case, unlike for many other medical products like drugs, it's possible for people to get vaccines through another route and are similar to OTC. (Plus not as fraught as vaccines for fatal diseases)

and maybe I am misunderstanding--they ARE using the natural experiment that some folks do not get the vaccine, through choice, lack of access, or simply didn't get around to it. Is your worry that there is a variable that correlates with lack of choosing to get this vaccine?

Another that George Davey Smith mentions in the talk is that those who aren't vaccinated and catch shingles have more contact with GPs and are therefore more likely to be diagnosed with dementia (or other conditions), an effect that's seen with other treatments & vaccines at those ages as well.